Valve opening/closing timing control apparatus

ABSTRACT

Configured is a valve opening/closing timing control apparatus that supports a torsion spring to an external position in a stable manner. In the valve opening/closing timing control apparatus, a spring holder is supported to a driven side rotary body and the spring holder forms a first engaging portion to which a first arm of the torsion spring is engaged. Further, in an outer wall of a driving side rotary body, there is formed a spring holding portion formed concave in a circumferential region centering around a rotational axis for allowing fitting-in of a part of an inner end of a coil portion of the torsion spring in a direction along the rotational axis.

TECHNICAL FIELD

The present invention relates to a valve opening/closing timing control apparatus including a torsion spring for displacing a rotational phase between a driving side rotary body and a driven side rotary body in a predetermined direction by an urging force.

BACKGROUND ART

As an example of a valve opening/closing timing control apparatus configured as above, PTL 1 discloses a technique having a torsion spring for urging a driven side rotary body (“an inner rotor” in the document) relative to a driving side rotary body (“an outer rotor” in the document) in an advancing direction.

In this PTL 1, a cylindrical portion is formed in a front plate which is fixed to a front face of the driving side rotary body and the torsion spring is accommodated in this cylindrical portion, and also one end of the torsion spring is engaged with the front plate and the other end thereof is engaged with the driven side rotary body. Further, in an inner face of the cylindrical portion, there is formed a spiral groove in form of a slope for contacting a first coiling turn of the torsion spring.

Further, PTL 2 discloses a technique including a driving side rotary body (“a housing” in the document) and a driven side rotary body (“a vane member” in the document) and the driven side rotary body includes a support member which supports a torsion spring.

In this PTL 2, the support member includes a restricting portion for restricting collapse of the torsion spring, the restricting portion being disposed on an outer side of a front plate provided on a front face side of the driving side rotary body, the torsion spring is disposed between the restricting portion and the front plate, and one end of this torsion spring is supported to the front plate and the other end thereof is supported to the restricting portion of the support member.

CITATION LIST Patent Literature

-   PTL 1: Japanese Unexamined Patent Application Publication No.     2003-247404 -   PTL 2: Japanese Unexamined Patent Application Publication No.     2007-278305

SUMMARY OF INVENTION Technical Problem

In the case of the configuration of PTL 1 wherein the torsion spring is accommodated in an accommodation space formed inside the valve opening/closing timing control apparatus, there is a need for a working step for forming the accommodation space and a mold becomes complicated in order to form such accommodation space. For these reasons, the technique invites increase of manufacture cost.

Further, in the case of the arrangement having the torsion spring in an accommodation space, the arrangement tends to invite intrusion of friction powder debris generated due to contact with the torsion spring at the time of its operation, into the apparatus.

To cope with such inconvenience as above, as disclosed in PTL 2, it is also conceivable to attach the arrangement of supporting the torsion spring to the support member (this will be referred to as “an urging unit” hereinafter) to the main body portion (the driving side rotary body and the driven side rotary body) of the valve opening/closing timing control apparatus.

With the above-described configuration of attaching the urging unit to the main body portion of the valve opening/closing timing control apparatus, it becomes possible to carry out a step of assembling the main body portion and a step of assembling the urging unit, separately. Thus, assembly is facilitate. Moreover, as it becomes unnecessary to form an accommodation space for the torsion spring inside the valve opening/closing timing control apparatus, manufacture cost reduction is made possible and prevention of intrusion of friction powder debris into the apparatus is made possible as well.

In the case of the configuration of providing the urging unit on the outer face of the main body portion of the valve opening/closing timing control apparatus, it is necessary to engage and support one end of the torsion spring to the driving side rotary body and also to hold the torsion spring at an appropriate position in a stable manner, in view of suppression of vibration at the time of rotation.

However, in the configuration of PTL 2, a base end portion of the torsion spring is supported by being wound around three protruding portions formed in the front plate. Thus, the front plate tends to be complicated. Hence, there remains room for improvement.

An object of the present invention is to configure a valve opening/closing timing control apparatus that supports a torsion spring to an external position in a stable manner.

Solution to Problem

According to a characterizing feature of the present invention, a valve opening/closing timing control apparatus comprises:

a driving side rotary body rotatable in synchronism with a crank shaft of an internal combustion engine and a driven side rotary body rotatable in unison and coaxially with a valve opening/closing cam shaft;

a fluid pressure type phase control mechanism for displacing a relative rotational phase between the driving side rotary body and the driven side rotary body in either an advancing direction or a retarding direction; and

an urging mechanism for applying an urging force between the driving side rotary body and the driven side rotary body for displacing the relative rotational phase in a predetermined direction;

wherein the urging mechanism includes a spring holder protruding along the rotational axis and connected to the driven side rotary body and a torsion spring for providing an urging force to the spring holder and the driving side rotary body;

wherein the torsion spring includes a wound-around coil portion, a first arm extending from one end of the coil portion and engaged with the spring holder and a second arm extending from the other end of the coil portion in a radial direction; and

wherein in an outer wall of the driving side rotary body, there are formed a concave spring holding portion supporting an end of the torsion spring and a groove-like arm holding portion holding the second arm.

With the above-described configuration, the spring holder is connected to the driven side rotary body and the coil portion of the torsion spring is disposed in the spring holder, and the first arm of this torsion spring is held by the spring holder. Further, a part of the torsion spring is fitted in the concave spring holding portion formed in the outer wall of the driving side rotary body and the second arm of the torsion spring is fitted in the groove-like arm holding portion formed in the outer wall of the driving side rotary body. As this holding portion allows fitting-in of the second arm in the radial direction, the holding state of the torsion spring can be confined short in the direction of the rotational axis.

As a result, there has been configured a valve opening/closing timing control apparatus that supports a torsion spring to an external position in a stable manner. In particular, as the second arm portion extends in the radial direction, there is no need to form a hole portion in the driving side rotary body for holding the second warm portion, unlike e.g. an arrangement that the second arm portion extends in the direction along the rotational axis. Thus, size increase of the driving side rotary body in the rotational axis direction can be suppressed. As a result, compactization of the apparatus is realized.

According to the present invention, preferably, the spring holding portion may be formed spirally along a shape of the end portion of the coil portion of the torsion spring.

With the above arrangement, when a part of the torsion spring is fitted in the spring holding portion, the axis of the coil portion of this torsion spring can be disposed under a posture in agreement with the rotational axis. Further, it becomes also possible to reduce a protrusion amount of the torsion spring in the rotational axis direction. As a result, as the gravity center position of the torsion spring is placed on the rotational axis, vibration at the time of rotation can be suppressed.

Moreover, as the coil portion of the torsion spring contacts a tilted face of the spring holding portion over a large face, reduction of frictional wear due to localized contact is made possible also.

According to the present invention, the spring holding portion can have a shape that holds a portion smaller than or equal to one turn amount of the end of the torsion spring.

With the above-described arrangement, displacement of the torsion spring in either direction about the rotational axis can be suppressed also. Also, as it is not necessary to cause the other portion of the torsion spring to contact any component constituting the apparatus, resistance at the time of relative rotational phase change can be reduced, so that frictional wear due to contact with the torsion spring can be suppressed as well.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a section view of a valve opening/closing timing control apparatus,

FIG. 2 is a section view taken along a line II-II in FIG. 1,

FIG. 3 is a view showing position relation between an urging unit and a front plate,

FIG. 4 is a section view showing the urging unit and the front plate under disassembled state thereof, and

FIG. 5 is an exploded perspective view of the valve opening/closing timing control apparatus.

DESCRIPTION OF EMBODIMENT

Next, an embodiment of the present invention will be explained with reference to the accompanying drawings.

Basic Configuration

As shown in FIG. 1 and FIG. 2, a valve opening/closing timing control apparatus A includes an outer rotor 20 as a “driving side rotary body”, an inner rotor 30 as a “driven side rotary body”, an urging unit 40 as an “urging mechanism” for urging a relative rotational phase between the outer rotor 20 and the inner rotor 30 in an advancing direction, and an electromagnetic control valve 50.

The outer rotor 20 is operably coupled to a crank shaft 1 of an engine E as an internal combustion engine via a timing belt 7 to be rotatable therewith in synchronism and disposed coaxially with a rotational axis X of an intake cam shaft 5. The inner rotor 30 is disposed coaxially with the rotational axis X, thus being encased within the outer rotor 20 and connected to the intake cam shaft 5 to be rotatable therewith.

This valve opening/closing timing control apparatus A includes the electromagnetic control valve 50 coaxially with the rotational axis X of the inner rotor 30. The valve opening/closing timing control apparatus A changes a relative rotational phase between the outer rotor 20 and the inner rotor 30 by controlling work oil by the electromagnetic control valve 50, thereby to control opening/closing timing of an intake valve 5V. Incidentally, the outer rotor 20 and the inner rotor 30 together function as a “phase control mechanism”.

The engine E is to be included in a vehicle such as a passenger car. This engine E includes the crank shaft 1 at a lower portion thereof, and a piston 3 is accommodated in a cylinder bore formed in a cylinder block 2 provided at an upper portion of the engine E. The engine E is configured as a 4 cycle engine with the piston 3 and the crank shaft 1 being connected via a connecting rod 4.

Incidentally, a transmission mechanism for transmitting rotational force of the crank shaft 1 to the valve opening/closing timing control apparatus A may employ a timing chain or may be configured such that the driving force of the crank shaft 1 is transmitted via a gear train having many gears.

Further, at an upper portion of the engine E, there are provided the intake cam shaft 5 and an exhaust cam shaft and also a hydraulic pump P driven by the driving force of the crank shaft 1 is provided. The intake cam shaft 5, as being rotated, opens/closes the intake valve 5V. The hydraulic pump P functions to feed lubricant oil reserved in an oil pan of the engine E as the work oil via a feed passage 8 to the electromagnetic control valve 50.

As the timing belt 7 is routed around an output pulley 6 formed on the crank shaft 1 of the engine E and a timing pulley 23P, the outer rotor 20 is rotated in synchronism with the crank shaft 1. Though not shown in the drawings, a timing pulley is provided also at a front end of the exhaust side cam shaft and the timing belt 7 is routed around this timing pulley also.

Incidentally, in the instant embodiment, the valve opening/closing timing control apparatus A is provided in the intake cam shaft 5. Alternatively, the valve opening/closing timing control apparatus A may be provided in the exhaust cam shaft or may be provided in both the intake cam shaft 5 and the exhaust cam shaft.

As shown in FIG. 2, the valve opening/closing timing control apparatus A is configured such that the outer rotor 20 is rotated in a driving rotational direction S by the driving force from the crank shaft 1. Further, the direction of relative rotation of the inner rotor 30 relative to the outer rotor 20 in the same direction as the driving rotational direction S will be referred to as an “advancing direction Sa” and its opposite direction will be referred to as a “retarding direction Sb”, respectively.

[Valve Opening/Closing Timing Control Apparatus]

The valve opening/closing timing control apparatus A, as shown in FIG. 1, FIG. 2 and FIG. 5, includes the outer rotor 20 and the inner rotor 30 and includes also a bush-like adapter 37 at a position sandwiched between the inner rotor 30 and the intake cam shaft 5.

The outer rotor 20 includes an outer rotor main body 21, a front plate 22 and a rear plate 23, with these members being integrated to each other by fastening of a plurality of fastener bolts 24. In the outer circumference of the rear plate 23, the timing pulley 23P is formed.

At a position sandwiched between the front plate 22 and the rear plate 23, the inner rotor 30 is disposed. The outer rotor main body 21 integrally forms a plurality of section portions 21T that protrude inwards in a radial direction relative to the rotational axis X.

The inner rotor 30 includes a cylindrical inner rotor main body 31 that contacts gaplessly protruding ends of the section portions 21T of the outer rotor main body 21, and a plurality of (four) vane portions 32 that protrude from the outer circumference of the inner rotor main body 31 between the adjacent section portions 21T so as to contact the inner circumferential face of the outer rotor main body 21.

With the above-described arrangement, at mid positions between adjacent section portions 21T in the rotational direction, a plurality of fluid pressure chambers C are formed on the outer circumferential side of the inner rotor main body 31. And, as these fluid pressure chambers C are partitioned from each other by the vane portions 32, advancing chambers Ca and retarding chambers Cb are formed.

Further, a connecting bolt 38 forms a bolt head portion 38H and a male thread portion 38S. As the male thread portion 38S is threaded to a female thread portion of the intake cam shaft 5, the inner rotor 30 is connected to the intake cam shaft 5. In particular, at the time of this connection, between the bolt head portion 38H and the intake cam shaft 5, the adapter 37, the inner rotor 30 and a seat portion 42 of a spring holder 41 will be clamped, thus being integrated to each other.

The connecting bolt 38 is formed cylindrical centering about the rotational axis X and in an inner hollow portion thereof, there are accommodated a spool 51 of the electromagnetic control valve 50 and a spool spring (not shown) for urging this in a protruding direction. The arrangement of this electromagnetic control valve 50 will be described later.

This valve opening/closing timing control apparatus A includes, as a phase control mechanism, a lock mechanism L for locking (fixing) the relative rotational phase between the outer rotor 20 and the inner rotor 30 to a most retarded phase. This lock mechanism L includes a locking member 25 that is guided into/out of a guide hole 26 formed in one vane portion 32 under a posture along the rotational axis X, a locking spring that urges the locking member 25 for its protrusion, and a locking recess formed in the rear plate 23.

At the time of an operation of the engine E, a variable torque applied from the intake cam shaft 5 acts in the retarding direction Sb. For this reason, in order to suppress the effect of such variable torque, an urging direction of the urging unit 40 is set to be displaced in the advancing direction Sa relative to the inner rotor 30. The arrangement of this urging unit 40 will be described later herein.

[Valve Opening/Closing Timing Control Apparatus: Oil Passage Arrangement]

The space for displacing the relative rotational phase in the advancing direction Sa by feeding of work oil is the advancing chamber Ca. Conversely, the space for displacing the relative rotational phase in the retarding direction Sb by feeding of work oil is the retarding chamber Cb. A relative rotational phase when the vane portion 32 reaches the operational end in the advancing direction Sa (including a phase adjacent the operational end of the vane portion 32 in the advancing direction Sa) will be referred to as the “most advanced phase”. A relative rotational phase when the vane portion 32 reaches the operational end in the retarding direction Sb (including a phase adjacent the operational end of the vane portion 32 in the regarding direction Sb) will be referred to as the “most retarded phase”.

The inner rotor main body 31 defines retarding flow passages 33 communicated to the retarding chambers Cb and advancing flow passages 34 communicated to the advancing chambers Ca, and the advancing chambers 34 are communicated to the locking recess.

With this valve opening/closing timing control apparatus A in operation, when the lock mechanism L is under a locked state, if the work oil is fed from the advancing flow passage 34 to the locking recess when the work oil is fed into the advancing chamber Ca, the locking member 25 is moved away from the locking recess against the urging force of the locking spring, thus releasing the locked state.

[Electromagnetic Control Valve and Oil Passage Arrangement]

As shown in FIG. 1, the electromagnetic control valve 50 includes the spool 51, the spool spring and an electromagnetic solenoid 54. More particularly, the spool 51 is disposed to be slidable in the direction along the rotational axis X in the inner space of the connecting bolt 38. The connecting bolt 38 includes a stopper 53 in the form of a stopper ring for fixing an outer end side operational position of the spool 51. Further, the spool spring applies an urging force that moves this spool 51 in the direction away from the intake cam shaft 5 (protrusion direction).

The electromagnetic solenoid 54 includes a plunger 54 a which operates to protrude by an amount in direct proportion with an amount of electric power fed to the solenoid therein. By a pressing force of this plunger 54 a, the spool 51 is operated. Further, the spool 51 is rotated in unison with the inner rotor 30 and the electromagnetic solenoid 54 is supported to the engine E, thus becoming inoperable.

The electromagnetic solenoid 54 is disposed at a position that places its plunger 54 a contactable with an outer end of the spool 51, and is maintained at a non-pressing position under no power supplied state, whereby the spool 51 is maintained at a retarding position. Further, when a predetermined electric power is supplied to the electromagnetic solenoid 54, the plunger 54 a reaches a pressing position on the inner end side, whereby the spool 51 is maintained at an advancing position. Further, when the electromagnetic solenoid 54 is supplied with electric power which is lower than the power for setting for the advancing position, a protrusion amount of the plunger 54 a is restricted, whereby the spool 51 is maintained at a neutral position which is midway between the advancing position and the retarding position.

Further, inside the connecting bolt 38, there is formed a flow passage for feeding the work oil to either the retarding flow passage 33 or the advancing flow passage 34 by controlling the work oil from the hydraulic pump P according to a position of the spool 51. Therefore, for example, if the spool 51 is operated to the retarding position by the electromagnetic solenoid 54 and then operated to the neutral position and further operated to the advancing position, in correspondence therewith, there will be provided a state of the work oil from the hydraulic pump P being fed to the retarding chamber Cb, a state of no work oil feeding/discharging and a state of the work oil being fed to the advancing chamber Ca, in this mentioned order.

[Valve Opening/Closing Timing Control Apparatus: Urging Unit]

The urging unit 40, as shown in FIG. 1 and FIGS. 3-5, consists essentially of the spring holder 41 and a torsion spring 46 supported to the spring holder 41.

In the spring holder 41, the seat portion 42 connected to the inner rotor main body 31 and a plurality (three in this embodiment) of protruding portions 43 formed to protrude from the seat portion 42 along the rotational axis X integrally with each other. Incidentally, the spring holder 41 may omit the seat portion 42. Further, a member connected to the inner rotor main body 31 and protruding along the rotational axis X can be used as the protruding portion 43.

At the center position of the seat portion 42, there is formed an insertion hole 42A into which the fastener bolt 24 is to be inserted. At a mid position between the protruding portions 43 that are adjacent each other in the circumferential direction in the outer circumference of the seat portion 42, an alignment portion 44 protruding outward is formed. And, in one of a plurality of (three in this embodiment) such alignment portions 44, there is formed a rotation restricting portion 44A that protrudes outward from the outer end.

The spring holder 41 is to be manufactured by press work of a metal plate, and the seat portion 42, the plurality of alignment portions 44, and the rotation restricting portion 44A will be disposed on a same virtual plane that assumes a posture perpendicular to the rotational axis X. Further, the plurality of protruding portions 43 respectively are formed with a set width and are formed in an arcuate shape so that outer circumferential faces thereof will be arranged on a circumference centering about the rotational axis X. Further, in order to facilitate bending of the protruding portions 43 in the course of the press work, a border portion between the base end portion of the protruding portion 43 and the base end portion of the alignment portion 44 is cut away in the direction of the seat portion 42, thus forming a cutout portion 42B.

At a lateral edge of one of the plurality of protruding portions 43, there is formed a first engaging portion 43A (an example of “engaging supporting portion”) provided in the form of a circumferentially cut-in recess. As the plurality of alignment portions 44 are fitted within an engaging recess 31A of the inner rotor main body 31, outer end edges 44E of the respective alignment portions 44 come into contact with a round inner circumferential face 31AE of the engaging recess 31A, thus effecting position fixing. In order to realize this position fixing, a virtual outer circumference circle interconnecting the respective outer end edges 44E is formed arcuate along the circumference of the circle centering about the rotational axis X. As will be described later herein, a diameter of the virtual outer circumference circle is an outer end diameter D3. Incidentally, with this arrangement, the above-described state of the alignment portions 44 being fitted in the engaging recess 31A is an engaged state of such a degree that allows relative rotation therebetween. When the rotation restricting portion 44A is fitted into a restricting recess 31B, the respective rotation is restricted.

The torsion spring 46 is disposed in a region surrounding the spring holder 41 and includes a wound-around coil portion 46A, a first arm 46B (one end) extending radially inward from an outer end position of the coil portion 46A in the direction along the rotational axis X and a second arm 46C (the other end) extending radially outward from an inner end position. Incidentally, the coil portion 46A may be disposed inside a space sectioned by the protruding portions 43.

As shown in FIG. 5, at the center position of the front plate 22, there is defined a through hole 22A having an inner diameter slightly greater than an outer circumference diameter D2 of the plurality of protruding portions 43 and a hole diameter D1 (inner diameter) centered around the rotational axis X. A virtual outer circumferential edge interconnecting outer circumferences of the plurality of protruding portions 43 as viewed in the direction along the rotational axis X constitutes the outer circumference diameter D2. Incidentally, an inner diameter of the coil portion 46A of the torsion spring 46 is set to a value sufficiently greater than the outer circumference diameter D2.

The outer end diameter D3 of the virtual outer circumferential edge interconnecting the outer ends of the plurality of alignment portions 44 as viewed in the direction along the rotational axis X is set greater than the hole diameter D1. Further, an inner circumference diameter D4 of the engaging recess 31A of the inner rotor main body 31 is set to a value slightly greater than the outer end diameter D3. This arrangement allows insertion of the protruding portions 43 having the outer circumference diameter D2 into the through hole 22A having the hole diameter D1. Further, the alignment portions 44 having the outer end diameter D3 greater than the hole diameter D1 of the through hole 22A are non-withdrawably held to the front plate 22. Moreover, the arrangement allows fitting of the alignment portions 44 having this outer end diameter D3 into the engaging recess 31A having the inner circumference diameter D4.

In the outer wall of the front plate 22 and at a circumferential region thereof surrounding the through hole 22A, there is formed a spring holding portion 22B in the form of a recess into which a part of the inner end position of the coil portion 46A of the torsion spring 46 is fitted. At a position overlapped with this spring holding portion 22B, there is formed a second engaging portion 22C (an example of “arm holding portion”) in the form of a groove extending outward continuously from this spring holding portion 22B.

As shown in FIG. 4, the spring holding portion 22B is formed spiral along the end shape of the coil portion 46A of the torsion spring 46. Namely, the spring holding portion 22B is formed as a tilted face which is tilted relative to the virtual plane perpendicular to the rotational axis X. As the spring holding portion 22B is formed with a tilt as described above, the depth of the spring holding portion 22B (the value in the direction along the rotational axis X) is not a constant value, but the depth of this spring holding portion 22B is set as a depth that allows accommodation of one turn of the torsion spring 46.

With the above-described arrangement of limiting the depth of the spring holding portion 22B, increase of thickness of the front plate 22 is restricted, thus suppressing enlargement of the valve opening/closing timing control apparatus A. Incidentally, as the torsion spring 46, it is also possible to employ a wire member having a round cross section.

The engaging recess 31A is formed by causing the area centered around the rotational axis X to be receded relative to the front plate side outer end face of the inner rotor main body 31. This engaging recess 31A is formed like a circle having the inner circumferential face 31AE centered around the rotational axis X. The inner circumference diameter D4 of this engaging recess 31A, as described hereinbefore, is set to a value slightly greater than the outer end diameter D3 of the virtual outer circumferential edge interconnecting the outer ends of the plurality of alignment portions 44, and at its outer circumferential portion, the restricting recess 31B is formed as a recess (see FIG. 5).

In this engaging recess 31A, the seat portion 42 of the spring holder 41 and the alignment portions 44 are fitted and in the restricting recess 31B, the rotation restricting portion 44A is fitted. And, the depths of the engaging recess 31A and the restricting recess 31B are set to values that agree with the thickness of the alignment portions 44 of the spring holder 41. With this arrangement, when the front plate 22 is connected to the outer rotor main body 21 with the plurality of fastener bolts 24, the alignment portions 44 of the spring holder 41 are pressed down by the outer circumference of the through hole 22A of the front plate 22, thus becoming un-withdrawable.

Incidentally, the restricting recess 31B may be formed at a plurality of portions of the engaging recess 31A. Further, in order to restrict relative rotation between the spring holder 41 and the inner rotor 30, a recess may be formed in the outer circumference of the alignment portion 44 and a protrusion engageable therewith may be formed in the inner circumference of the engaging recess 31A. Since the restricting recess 31B is formed in the radial direction as described above, there occurs no increase in the thickness of the inner rotor 30, in comparison with e.g. an arrangement in the form of a hole along the rotational axis X.

[Assembly of Urging Unit]

The rear plate 23 is disposed at the rear portion of the outer rotor main body 21 and the inner rotor main body 31 is fitted in its inside and the spool 51 etc. are accommodated inside the connecting bolt 38.

Next, the protruding portions 43 of the spring holder 41 are inserted into the through hole 22A of the front plate 22 from the rear face side thereof and the torsion spring 46 is disposed from the front face side to surround the plurality of protruding portions 43.

When the torsion spring 46 is to be disposed in the manner described above, a portion of the coil portion 46A is fitted into the spring holding portion 22B of the front plate 22 and the second arm 46C of the torsion spring 46 is fitted into the second engaging portion 22C. Further, the first arm 46B of the torsion spring 46 is engaged to the first engaging portion 43A of the protruding portion 43 to be held therein.

Next, the alignment portions 44 of the spring holder 41 are fitted into the engaging recess 31A of the inner rotor main body 31 and the rotation restricting portion 44A is fitted into the restricting recess 31B. With this, as the outer end edges 44E of the plurality of alignment portions 44 come into contact with the cylindrical inner circumferential face 31AE of the engaging recess 31A, position-fixing of the spring holder 41 is effected in such a manner as to hold the gravity center position of the spring holder 41 at the position of the rotational axis X. Whereby, there is realized a state in which the inner rotor main body 31 and the spring holder 41 are rotatable in unison with each other.

Next, the front plate 22 is placed over the outer rotor main body 21 and these are connected to each other by the fastener bolts 24. Further, the connecting bolt 38 is inserted into the through hole 42A of the seat portion 42 of the spring holder 41 and the male thread portion 38S of this connecting bolt 38 is threaded to the female thread portion of the intake cam shaft 5, thus completing the fastening.

With the above, the intake cam shaft 5, the inner rotor 30 and the spring holder 41 are integrated to each other, thus completing the valve opening/closing timing control apparatus A. Under this completed state, as the alignment portions 44 of the spring holder 41 are pressed down by the outer circumference of the through hole 22A of the front plate 22, floating-up of the spring holder 41 is prevented.

Under this completed state, the torsion spring 46 of the urging unit 40 provides an urging force to displace the inner rotor 30 in the advancing direction Sa relative to the outer rotor 20. Also, as a portion of the coil portion 46A of the torsion spring 46 which portion is adjacent the front plate 22 is fitted into the spring holding portion 22B under the tilted posture, the torsion spring 46 can be supported with the axis of the coil portion 46A of this torsion spring 46 being in agreement with the rotational axis X. Moreover, since the inner circumference of the coil portion 46A of the torsion spring 46 is disposed at the position away from the outer circumferences of the protruding portions 43, at the time of change of relative rotational phase, no resistance is applied therebetween, so no frictional wear of the outer circumferences of the protruding portions 43 will occur, either.

Function and Effect of Embodiment

In the case of the arrangement wherein the urging unit 40 protrudes from the main body portion (phase control mechanism) of the valve opening/closing timing control apparatus A, it is important that the gravity center position of this urging unit 40 be in agreement with the rotational axis X during rotation. To this end, in case the spring holder 41 is attached to the inner rotor main body 31 as provided in the present invention, by fitting the alignment portions 44 into the engaging recess 31A of the inner rotor main body 31 for position fixing, the gravity center position of the spring holder 41 can be positioned coaxial with the rotational axis X. Moreover, only with fitting-in of the rotation restricting portion 44A of the spring holder 41, the spring holder 41 and the inner rotor 30 can be made rotatable in union with each other.

In comparison with an arrangement of fixing the spring holder 41 to the inner rotor 30 by press-fitting, no deformation occurs in the inner rotor 30 and no increase of sliding resistance in association with deformation of such press-fitting operation occurs, either. Furthermore, for instance, in the case of an arrangement wherein one end of the torsion spring 46 is directly engaged to the outer rotor 20 or the inner rotor 30, such arrangement requires enhancement of strength of the engagement portion. In contrast, by using the spring holder 41, there is no need to increase the strength of either of the rotors and no frictional wear occurs at the portion engaged with the spring, either.

In the present invention, the inner end side of the coil portion 46A of the torsion spring 46 in the direction of the rotational axis X is supported as being fitted into the tilted spring holding portion 28 of the front plate 22. With this, the axial position of the coil portion 46A of the torsion spring 46 is in agreement with the rotational axis X and no vibration occurs in the torsion spring 46 during rotation. Further, since the portion of the coil portion 46A of the coil spring 46 comes into contact with the titled face of the spring holding portion 22B over a large area, reduction of frictional wear due to locally concentrated contact is realized also.

Since the hole diameter D1 of the through hole 22A of the front plate 22 is made smaller than the outer end diameter D3 of the plurality of alignment portions 44, the front plate 22 presses down the spring holder 41, thus preventing float-up of the spring holder 41.

With the valve opening/closing timing control apparatus A having the above-described configuration, leak of work oil occurs between the outer rotor 20 and the inner rotor 30. And, by causing such leaked work oil to be discharged to the outside via the through hole 22A of the front plate 22, the work oil is fed between the torsion spring 46 and the spring holding portion 22B, whereby frictional wear of the spring holding portion 22B can be suppressed.

INDUSTRIAL APPLICABILITY

The present invention can be utilized in a valve opening/closing timing control apparatus having a mechanism for urging a relative rotational phase between a driving side rotary body and a driven side rotary body in a predetermined direction.

REFERENCE SIGNS LIST

-   -   1: crank shaft     -   5: cam shaft (intake cam shaft)     -   20: driving side rotary body (outer rotor)     -   22B: spring holding portion     -   22C: arm holding portion (second engaging portion)     -   30: driven side rotary body (inner rotor)     -   40: urging mechanism (urging unit)     -   41: spring holder     -   43A: first engaging portion     -   46: torsion spring     -   46A: coil portion     -   46B: first arm     -   46C: second arm     -   E: internal combustion engine (engine)     -   Sa: advancing direction     -   Sb: retarding direction     -   X: rotational axis 

1. A valve opening/closing timing control apparatus comprising: a driving side rotary body rotatable in synchronism with a crank shaft of an internal combustion engine and a driven side rotary body rotatable in unison and coaxially with a valve opening/closing cam shaft; a fluid pressure type phase control mechanism for displacing a relative rotational phase between the driving side rotary body and the driven side rotary body in either an advancing direction or a retarding direction; and an urging mechanism for applying an urging force between the driving side rotary body and the driven side rotary body for displacing the relative rotational phase in a predetermined direction; wherein the urging mechanism includes a spring holder protruding along the rotational axis and connected to the driven side rotary body and a torsion spring for providing an urging force to the spring holder and the driving side rotary body; wherein the torsion spring includes a wound-around coil portion, a first arm extending from one end of the coil portion and engaged with the spring holder and a second arm extending from the other end of the coil portion in a radial direction; and wherein in an outer wall of the driving side rotary body, there are formed a concave spring holding portion supporting an end of the torsion spring and a groove-like arm holding portion holding the second arm.
 2. The valve opening/closing timing control apparatus according to claim 1, wherein the spring holding portion is formed spirally along a shape of the end portion of the coil portion of the torsion spring.
 3. The valve opening/closing timing control apparatus according to claim 1, wherein the spring holding portion has a shape that holds a portion smaller than or equal to one turn amount of the end of the torsion spring. 